//最底层的可读流对象

const { Readable } = require("stream");
//实例化对象
let reader = new Readable();

for (let c = 'a'.charCodeAt(0); c <= 'z'.charCodeAt(0); c++) {
    //转换成字符
    reader.push(String.fromCharCode(c));
}

//没有写入的过程
reader.push(null);

reader.pipe(process.stdout);

//可写流 writable.write end